SigningPrivateKey (Javadocs [I2P+ 2.11.0+]

java.lang.Object
- net.i2p.data.SimpleDataStructure
- - net.i2p.data.SigningPrivateKey

All Implemented Interfaces:

Destroyable, DataStructure

Direct Known Subclasses:

RSASigningPrivateCrtKey
```
public class SigningPrivateKey
extends SimpleDataStructure
implements Destroyable
```
Cryptographic private key for digital signature generation in I2P.
SigningPrivateKey provides signature generation capabilities:
- Default Algorithm: DSA-SHA1 (20 bytes)
- Modern Support: Variable length and type support since 0.9.8
- Key Structure: Contains only private exponent/coordinates
- Security: Implements Destroyable for secure cleanup
Supported Algorithms:
- DSA-SHA1: Legacy algorithm, 20-byte keys
- ECDSA-P256: Modern algorithm, variable length keys
- EdDSA-Ed25519: Modern algorithm, 32-byte keys
- Future Types: Extensible design for new algorithms
Key Format:
- DSA: 20-byte private exponent (x)
- ECDSA: Variable length private scalar
- EdDSA: 32-byte private seed
- Type Encoding: Algorithm type embedded in data
Usage:
- Signature Generation: Sign data with corresponding SigningPublicKey
- Identity Creation: Part of Destination identity
- LeaseSet Signing: Sign LeaseSet for network publication
- Router Identity: Sign router information for NetDb
Security Considerations:
- Confidentiality: Private signing keys must never be exposed
- Secure Destruction: Call destroy() when no longer needed
- Memory Protection: Zeroize memory after use
- Algorithm Choice: Prefer modern algorithms (Ed25519, ECDSA-P256)
Blinding Support:
- Key Blinding: Support for generating blinded key variants
- Privacy: Enable anonymous service endpoints
- BlindData: Integration with BlindData for blinding operations
Performance Features:
- Efficient Storage: Optimized byte representation
- Factory Methods: Static creation methods for consistency
- Fast Operations: Optimized for high-frequency signing
Migration Path:
- Legacy: DSA-SHA1 for backward compatibility
- Modern: Ed25519 for better performance and security
- Transition: Mixed algorithm support during migration
Thread Safety:
- Immutable Data: Key data cannot be modified after creation
- Safe Destruction: Thread-safe key zeroization
- Exclusive Use: Each instance should be used by only one thread

Field Summary

Fields
Modifier and Type Field and Description

static int KEYSIZE_BYTES
- Fields inherited from class net.i2p.data.SimpleDataStructure
  _data

Fields
Modifier and Type	Field and Description
`static int`	`KEYSIZE_BYTES`

Constructor Summary

Constructors
Constructor and Description
`SigningPrivateKey()`
`SigningPrivateKey(byte[] data)`
`SigningPrivateKey(SigType type)`
`SigningPrivateKey(SigType type, byte[] data)`
`SigningPrivateKey(String base64Data)` constructs from base64

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`SigningPrivateKey`	`blind(SigningPrivateKey alpha)` Only for SigType EdDSA_SHA512_Ed25519
`void`	`destroy()` javax.security.auth.Destroyable interface
`boolean`	`equals(Object obj)` Warning - this returns true for two different classes with the same size and same data, e.g.
`SigType`	`getType()` Gets the signature type of this private key.
`int`	`hashCode()` We assume the data has enough randomness in it, so use the first 4 bytes for speed.
`boolean`	`isDestroyed()` javax.security.auth.Destroyable interface
`boolean`	`isOffline()` Constant time
`int`	`length()` The legal length of the byte array in this data structure
`SigningPublicKey`	`toPublic()` Converts this signing private key to its public equivalent.
`String`	`toString()`

Methods inherited from class net.i2p.data.SimpleDataStructure
calculateHash, fromBase64, fromByteArray, getData, read, readBytes, setData, toBase64, toByteArray, writeBytes

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - KEYSIZE_BYTES
```
public static final int KEYSIZE_BYTES
```
- Constructor Detail
  - SigningPrivateKey
```
public SigningPrivateKey()
```
  - SigningPrivateKey
```
public SigningPrivateKey(byte[] data)
```
  - SigningPrivateKey
```
public SigningPrivateKey(SigType type)
```
  - SigningPrivateKey
```
public SigningPrivateKey(SigType type,
                         byte[] data)
```
  - SigningPrivateKey
```
public SigningPrivateKey(String base64Data)
                  throws DataFormatException
```
    constructs from base64
    
    Parameters:
    
    base64Data - a string of base64 data (the output of .toBase64() called on a prior instance of SigningPrivateKey
    
    Throws:
    
    DataFormatException
- Method Detail
  - blind
```
public SigningPrivateKey blind(SigningPrivateKey alpha)
```
    Only for SigType EdDSA_SHA512_Ed25519
    
    Parameters:
    
    alpha - the secret data
    
    Throws:
    
    UnsupportedOperationException - unless supported
  - destroy
```
public void destroy()
```
    javax.security.auth.Destroyable interface
    
    Specified by:
    
    destroy in interface Destroyable
  - equals
```
public boolean equals(Object obj)
```
    Description copied from class: SimpleDataStructure
    
    Warning - this returns true for two different classes with the same size and same data, e.g. SessionKey and SessionTag, but you wouldn't put them in the same Set, would you?
    
    Overrides:
    
    equals in class SimpleDataStructure
  - getType
```
public SigType getType()
```
    Gets the signature type of this private key.
  - hashCode
```
public int hashCode()
```
    Description copied from class: SimpleDataStructure
    
    We assume the data has enough randomness in it, so use the first 4 bytes for speed. If this is not the case, override in the extending class.
    
    Overrides:
    
    hashCode in class SimpleDataStructure
  - isDestroyed
```
public boolean isDestroyed()
```
    javax.security.auth.Destroyable interface
    
    Specified by:
    
    isDestroyed in interface Destroyable
  - isOffline
```
public boolean isOffline()
```
    Constant time
    
    Returns:
    
    true if all zeros
  - length
```
public int length()
```
    Description copied from class: SimpleDataStructure
    
    The legal length of the byte array in this data structure
    
    Specified by:
    
    length in class SimpleDataStructure
  - toPublic
```
public SigningPublicKey toPublic()
```
    Converts this signing private key to its public equivalent. As of 0.9.16, supports all key types.
    
    Returns:
    
    a SigningPublicKey object derived from this private key
    
    Throws:
    
    IllegalArgumentException - on bad key or unknown or unsupported type
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class SimpleDataStructure

Class SigningPrivateKey

Field Summary

Fields inherited from class net.i2p.data.SimpleDataStructure

Constructor Summary

Method Summary

Methods inherited from class net.i2p.data.SimpleDataStructure

Methods inherited from class java.lang.Object

Field Detail

KEYSIZE_BYTES

Constructor Detail

SigningPrivateKey

SigningPrivateKey

SigningPrivateKey

SigningPrivateKey

SigningPrivateKey

Method Detail

blind

destroy

equals

getType

hashCode

isDestroyed

isOffline

length

toPublic

toString